3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License as published by
5 * the Free Software Foundation; either version 2 of the License, or
6 * (at your option) any later version.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
16 * http://www.gnu.org/copyleft/gpl.html
21 use MediaWiki\Logger\LoggerFactory
;
22 use MediaWiki\MediaWikiServices
;
24 use Wikimedia\Rdbms\DBError
;
27 * Handler class for MWExceptions
30 class MWExceptionHandler
{
31 const CAUGHT_BY_HANDLER
= 'mwe_handler'; // error reported by this exception handler
32 const CAUGHT_BY_OTHER
= 'other'; // error reported by direct logException() call
35 * @var string $reservedMemory
37 protected static $reservedMemory;
39 * @var array $fatalErrorTypes
41 protected static $fatalErrorTypes = [
42 E_ERROR
, E_PARSE
, E_CORE_ERROR
, E_COMPILE_ERROR
, E_USER_ERROR
,
43 /* HHVM's FATAL_ERROR level */ 16777217,
46 * @var bool $handledFatalCallback
48 protected static $handledFatalCallback = false;
51 * Install handlers with PHP.
53 public static function installHandler() {
54 set_exception_handler( 'MWExceptionHandler::handleUncaughtException' );
55 set_error_handler( 'MWExceptionHandler::handleError' );
57 // Reserve 16k of memory so we can report OOM fatals
58 self
::$reservedMemory = str_repeat( ' ', 16384 );
59 register_shutdown_function( 'MWExceptionHandler::handleFatalError' );
63 * Report an exception to the user
64 * @param Exception|Throwable $e
66 protected static function report( $e ) {
68 // Try and show the exception prettily, with the normal skin infrastructure
69 if ( $e instanceof MWException
) {
70 // Delegate to MWException until all subclasses are handled by
71 // MWExceptionRenderer and MWException::report() has been
75 MWExceptionRenderer
::output( $e, MWExceptionRenderer
::AS_PRETTY
);
77 } catch ( Exception
$e2 ) {
78 // Exception occurred from within exception handler
79 // Show a simpler message for the original exception,
80 // don't try to invoke report()
81 MWExceptionRenderer
::output( $e, MWExceptionRenderer
::AS_RAW
, $e2 );
86 * Roll back any open database transactions and log the stack trace of the exception
88 * This method is used to attempt to recover from exceptions
91 * @param Exception|Throwable $e
93 public static function rollbackMasterChangesAndLog( $e ) {
94 $services = MediaWikiServices
::getInstance();
95 if ( !$services->isServiceDisabled( 'DBLoadBalancerFactory' ) ) {
96 // Rollback DBs to avoid transaction notices. This might fail
97 // to rollback some databases due to connection issues or exceptions.
98 // However, any sane DB driver will rollback implicitly anyway.
100 $services->getDBLoadBalancerFactory()->rollbackMasterChanges( __METHOD__
);
101 } catch ( DBError
$e2 ) {
102 // If the DB is unreacheable, rollback() will throw an error
103 // and the error report() method might need messages from the DB,
104 // which would result in an exception loop. PHP may escalate such
105 // errors to "Exception thrown without a stack frame" fatals, but
106 // it's better to be explicit here.
107 self
::logException( $e2, self
::CAUGHT_BY_HANDLER
);
111 self
::logException( $e, self
::CAUGHT_BY_HANDLER
);
115 * Callback to use with PHP's set_exception_handler.
118 * @param Exception|Throwable $e
120 public static function handleUncaughtException( $e ) {
121 self
::handleException( $e );
123 // Make sure we don't claim success on exit for CLI scripts (T177414)
125 register_shutdown_function(
134 * Exception handler which simulates the appropriate catch() handling:
138 * } catch ( Exception $e ) {
140 * } catch ( Exception $e ) {
141 * echo $e->__toString();
145 * @param Exception|Throwable $e
147 public static function handleException( $e ) {
148 self
::rollbackMasterChangesAndLog( $e );
153 * Handler for set_error_handler() callback notifications.
155 * Receive a callback from the interpreter for a raised error, create an
156 * ErrorException, and log the exception to the 'error' logging
157 * channel(s). If the raised error is a fatal error type (only under HHVM)
158 * delegate to handleFatalError() instead.
162 * @param int $level Error level raised
163 * @param string $message
164 * @param string $file
170 public static function handleError(
171 $level, $message, $file = null, $line = null
173 if ( in_array( $level, self
::$fatalErrorTypes ) ) {
174 return call_user_func_array(
175 'MWExceptionHandler::handleFatalError', func_get_args()
179 // Map error constant to error name (reverse-engineer PHP error
182 case E_RECOVERABLE_ERROR
:
183 $levelName = 'Error';
184 $severity = LogLevel
::ERROR
;
188 case E_COMPILE_WARNING
:
190 $levelName = 'Warning';
191 $severity = LogLevel
::WARNING
;
195 $levelName = 'Notice';
196 $severity = LogLevel
::INFO
;
199 $levelName = 'Strict Standards';
200 $severity = LogLevel
::DEBUG
;
203 case E_USER_DEPRECATED
:
204 $levelName = 'Deprecated';
205 $severity = LogLevel
::INFO
;
208 $levelName = 'Unknown error';
209 $severity = LogLevel
::ERROR
;
213 $e = new ErrorException( "PHP $levelName: $message", 0, $level, $file, $line );
214 self
::logError( $e, 'error', $severity );
216 // This handler is for logging only. Return false will instruct PHP
217 // to continue regular handling.
222 * Dual purpose callback used as both a set_error_handler() callback and
223 * a registered shutdown function. Receive a callback from the interpreter
224 * for a raised error or system shutdown, check for a fatal error, and log
225 * to the 'fatal' logging channel.
227 * Special handling is included for missing class errors as they may
228 * indicate that the user needs to install 3rd-party libraries via
229 * Composer or other means.
233 * @param int $level Error level raised
234 * @param string $message Error message
235 * @param string $file File that error was raised in
236 * @param int $line Line number error was raised at
237 * @param array $context Active symbol table point of error
238 * @param array $trace Backtrace at point of error (undocumented HHVM
240 * @return bool Always returns false
242 public static function handleFatalError(
243 $level = null, $message = null, $file = null, $line = null,
244 $context = null, $trace = null
246 // Free reserved memory so that we have space to process OOM
248 self
::$reservedMemory = null;
250 if ( $level === null ) {
251 // Called as a shutdown handler, get data from error_get_last()
252 if ( static::$handledFatalCallback ) {
253 // Already called once (probably as an error handler callback
254 // under HHVM) so don't log again.
258 $lastError = error_get_last();
259 if ( $lastError !== null ) {
260 $level = $lastError['type'];
261 $message = $lastError['message'];
262 $file = $lastError['file'];
263 $line = $lastError['line'];
270 if ( !in_array( $level, self
::$fatalErrorTypes ) ) {
271 // Only interested in fatal errors, others should have been
272 // handled by MWExceptionHandler::handleError
276 $msg = "[{exception_id}] PHP Fatal Error: {$message}";
278 // Look at message to see if this is a class not found failure
279 // HHVM: Class undefined: foo
280 // PHP5: Class 'foo' not found
281 if ( preg_match( "/Class (undefined: \w+|'\w+' not found)/", $msg ) ) {
282 // phpcs:disable Generic.Files.LineLength
286 MediaWiki or an installed extension requires this class but it is not embedded directly in MediaWiki's git repository and must be installed separately by the end user.
288 Please see <a href="https://www.mediawiki.org/wiki/Download_from_Git#Fetch_external_libraries">mediawiki.org</a> for help on installing the required components.
293 // We can't just create an exception and log it as it is likely that
294 // the interpreter has unwound the stack already. If that is true the
295 // stacktrace we would get would be functionally empty. If however we
296 // have been called as an error handler callback *and* HHVM is in use
297 // we will have been provided with a useful stacktrace that we can
299 $trace = $trace ?
: debug_backtrace();
300 $logger = LoggerFactory
::getInstance( 'fatal' );
301 $logger->error( $msg, [
302 'fatal_exception' => [
303 'class' => ErrorException
::class,
304 'message' => "PHP Fatal Error: {$message}",
308 'trace' => static::redactTrace( $trace ),
310 'exception_id' => wfRandomString( 8 ),
311 'caught_by' => self
::CAUGHT_BY_HANDLER
314 // Remember call so we don't double process via HHVM's fatal
315 // notifications and the shutdown hook behavior
316 static::$handledFatalCallback = true;
321 * Generate a string representation of an exception's stack trace
323 * Like Exception::getTraceAsString, but replaces argument values with
324 * argument type or class name.
326 * @param Exception|Throwable $e
328 * @see prettyPrintTrace()
330 public static function getRedactedTraceAsString( $e ) {
331 return self
::prettyPrintTrace( self
::getRedactedTrace( $e ) );
335 * Generate a string representation of a stacktrace.
337 * @param array $trace
338 * @param string $pad Constant padding to add to each line of trace
342 public static function prettyPrintTrace( array $trace, $pad = '' ) {
346 foreach ( $trace as $level => $frame ) {
347 if ( isset( $frame['file'] ) && isset( $frame['line'] ) ) {
348 $text .= "{$pad}#{$level} {$frame['file']}({$frame['line']}): ";
350 // 'file' and 'line' are unset for calls via call_user_func
351 // (T57634) This matches behaviour of
352 // Exception::getTraceAsString to instead display "[internal
354 $text .= "{$pad}#{$level} [internal function]: ";
357 if ( isset( $frame['class'] ) && isset( $frame['type'] ) && isset( $frame['function'] ) ) {
358 $text .= $frame['class'] . $frame['type'] . $frame['function'];
359 } elseif ( isset( $frame['function'] ) ) {
360 $text .= $frame['function'];
362 $text .= 'NO_FUNCTION_GIVEN';
365 if ( isset( $frame['args'] ) ) {
366 $text .= '(' . implode( ', ', $frame['args'] ) . ")\n";
373 $text .= "{$pad}#{$level} {main}";
379 * Return a copy of an exception's backtrace as an array.
381 * Like Exception::getTrace, but replaces each element in each frame's
382 * argument array with the name of its class (if the element is an object)
383 * or its type (if the element is a PHP primitive).
386 * @param Exception|Throwable $e
389 public static function getRedactedTrace( $e ) {
390 return static::redactTrace( $e->getTrace() );
394 * Redact a stacktrace generated by Exception::getTrace(),
395 * debug_backtrace() or similar means. Replaces each element in each
396 * frame's argument array with the name of its class (if the element is an
397 * object) or its type (if the element is a PHP primitive).
400 * @param array $trace Stacktrace
401 * @return array Stacktrace with arugment values converted to data types
403 public static function redactTrace( array $trace ) {
404 return array_map( function ( $frame ) {
405 if ( isset( $frame['args'] ) ) {
406 $frame['args'] = array_map( function ( $arg ) {
407 return is_object( $arg ) ?
get_class( $arg ) : gettype( $arg );
415 * Get the ID for this exception.
417 * The ID is saved so that one can match the one output to the user (when
418 * $wgShowExceptionDetails is set to false), to the entry in the debug log.
421 * @deprecated since 1.27: Exception IDs are synonymous with request IDs.
422 * @param Exception|Throwable $e
425 public static function getLogId( $e ) {
426 wfDeprecated( __METHOD__
, '1.27' );
427 return WebRequest
::getRequestId();
431 * If the exception occurred in the course of responding to a request,
432 * returns the requested URL. Otherwise, returns false.
435 * @return string|false
437 public static function getURL() {
439 if ( !isset( $wgRequest ) ||
$wgRequest instanceof FauxRequest
) {
442 return $wgRequest->getRequestURL();
446 * Get a message formatting the exception message and its origin.
449 * @param Exception|Throwable $e
452 public static function getLogMessage( $e ) {
453 $id = WebRequest
::getRequestId();
454 $type = get_class( $e );
455 $file = $e->getFile();
456 $line = $e->getLine();
457 $message = $e->getMessage();
458 $url = self
::getURL() ?
: '[no req]';
460 return "[$id] $url $type from line $line of $file: $message";
464 * Get a normalised message for formatting with PSR-3 log event context.
466 * Must be used together with `getLogContext()` to be useful.
469 * @param Exception|Throwable $e
472 public static function getLogNormalMessage( $e ) {
473 $type = get_class( $e );
474 $file = $e->getFile();
475 $line = $e->getLine();
476 $message = $e->getMessage();
478 return "[{exception_id}] {exception_url} $type from line $line of $file: $message";
482 * @param Exception|Throwable $e
485 public static function getPublicLogMessage( $e ) {
486 $reqId = WebRequest
::getRequestId();
487 $type = get_class( $e );
488 return '[' . $reqId . '] '
489 . gmdate( 'Y-m-d H:i:s' ) . ': '
490 . 'Fatal exception of type "' . $type . '"';
494 * Get a PSR-3 log event context from an Exception.
496 * Creates a structured array containing information about the provided
497 * exception that can be used to augment a log message sent to a PSR-3
500 * @param Exception|Throwable $e
501 * @param string $catcher CAUGHT_BY_* class constant indicating what caught the error
504 public static function getLogContext( $e, $catcher = self
::CAUGHT_BY_OTHER
) {
507 'exception_id' => WebRequest
::getRequestId(),
508 'exception_url' => self
::getURL() ?
: '[no req]',
509 'caught_by' => $catcher
514 * Get a structured representation of an Exception.
516 * Returns an array of structured data (class, message, code, file,
517 * backtrace) derived from the given exception. The backtrace information
518 * will be redacted as per getRedactedTraceAsArray().
520 * @param Exception|Throwable $e
521 * @param string $catcher CAUGHT_BY_* class constant indicating what caught the error
525 public static function getStructuredExceptionData( $e, $catcher = self
::CAUGHT_BY_OTHER
) {
526 global $wgLogExceptionBacktrace;
529 'id' => WebRequest
::getRequestId(),
530 'type' => get_class( $e ),
531 'file' => $e->getFile(),
532 'line' => $e->getLine(),
533 'message' => $e->getMessage(),
534 'code' => $e->getCode(),
535 'url' => self
::getURL() ?
: null,
536 'caught_by' => $catcher
539 if ( $e instanceof ErrorException
&&
540 ( error_reporting() & $e->getSeverity() ) === 0
542 // Flag surpressed errors
543 $data['suppressed'] = true;
546 if ( $wgLogExceptionBacktrace ) {
547 $data['backtrace'] = self
::getRedactedTrace( $e );
550 $previous = $e->getPrevious();
551 if ( $previous !== null ) {
552 $data['previous'] = self
::getStructuredExceptionData( $previous, $catcher );
559 * Serialize an Exception object to JSON.
561 * The JSON object will have keys 'id', 'file', 'line', 'message', and
562 * 'url'. These keys map to string values, with the exception of 'line',
563 * which is a number, and 'url', which may be either a string URL or or
564 * null if the exception did not occur in the context of serving a web
567 * If $wgLogExceptionBacktrace is true, it will also have a 'backtrace'
568 * key, mapped to the array return value of Exception::getTrace, but with
569 * each element in each frame's "args" array (if set) replaced with the
570 * argument's class name (if the argument is an object) or type name (if
571 * the argument is a PHP primitive).
573 * @par Sample JSON record ($wgLogExceptionBacktrace = false):
577 * "type": "MWException",
578 * "file": "/var/www/mediawiki/includes/cache/MessageCache.php",
580 * "message": "Non-string key given",
581 * "url": "/wiki/Main_Page"
585 * @par Sample JSON record ($wgLogExceptionBacktrace = true):
589 * "type": "MWException",
590 * "file": "/vagrant/mediawiki/includes/cache/MessageCache.php",
592 * "message": "Non-string key given",
593 * "url": "/wiki/Main_Page",
595 * "file": "/vagrant/mediawiki/extensions/VisualEditor/VisualEditor.hooks.php",
598 * "class": "MessageCache",
606 * @param Exception|Throwable $e
607 * @param bool $pretty Add non-significant whitespace to improve readability (default: false).
608 * @param int $escaping Bitfield consisting of FormatJson::.*_OK class constants.
609 * @param string $catcher CAUGHT_BY_* class constant indicating what caught the error
610 * @return string|false JSON string if successful; false upon failure
612 public static function jsonSerializeException(
613 $e, $pretty = false, $escaping = 0, $catcher = self
::CAUGHT_BY_OTHER
615 return FormatJson
::encode(
616 self
::getStructuredExceptionData( $e, $catcher ),
623 * Log an exception to the exception log (if enabled).
625 * This method must not assume the exception is an MWException,
626 * it is also used to handle PHP exceptions or exceptions from other libraries.
629 * @param Exception|Throwable $e
630 * @param string $catcher CAUGHT_BY_* class constant indicating what caught the error
632 public static function logException( $e, $catcher = self
::CAUGHT_BY_OTHER
) {
633 if ( !( $e instanceof MWException
) ||
$e->isLoggable() ) {
634 $logger = LoggerFactory
::getInstance( 'exception' );
636 self
::getLogNormalMessage( $e ),
637 self
::getLogContext( $e, $catcher )
640 $json = self
::jsonSerializeException( $e, false, FormatJson
::ALL_OK
, $catcher );
641 if ( $json !== false ) {
642 $logger = LoggerFactory
::getInstance( 'exception-json' );
643 $logger->error( $json, [ 'private' => true ] );
646 Hooks
::run( 'LogException', [ $e, false ] );
651 * Log an exception that wasn't thrown but made to wrap an error.
654 * @param ErrorException $e
655 * @param string $channel
656 * @param string $level
658 protected static function logError(
659 ErrorException
$e, $channel, $level = LogLevel
::ERROR
661 $catcher = self
::CAUGHT_BY_HANDLER
;
662 // The set_error_handler callback is independent from error_reporting.
663 // Filter out unwanted errors manually (e.g. when
664 // MediaWiki\suppressWarnings is active).
665 $suppressed = ( error_reporting() & $e->getSeverity() ) === 0;
666 if ( !$suppressed ) {
667 $logger = LoggerFactory
::getInstance( $channel );
670 self
::getLogNormalMessage( $e ),
671 self
::getLogContext( $e, $catcher )
675 // Include all errors in the json log (surpressed errors will be flagged)
676 $json = self
::jsonSerializeException( $e, false, FormatJson
::ALL_OK
, $catcher );
677 if ( $json !== false ) {
678 $logger = LoggerFactory
::getInstance( "{$channel}-json" );
679 $logger->log( $level, $json, [ 'private' => true ] );
682 Hooks
::run( 'LogException', [ $e, $suppressed ] );